1. Field of the Invention
This invention relates to an image processing apparatus and method, and more particularly, to an apparatus which can process images of a plurality of kinds of image signals.
2. Description of the Related Art
Recently, many kinds of copiers have become able to deal with not only black-and-white prints but also color prints, and copiers which can print not only color originals but also images of image signals have also been commercialized.
In accordance with the recent progress of semiconductor technology, digital processing of image information, such as video signals or the like, has spread widely, and there has arisen a desire to be able to supply video signals to a color printing apparatus from a video signal source in the form of digital signals.
An explanation will now be provided of a case wherein, for example, NTSC composite signals are used as video signals. When digitizing NTSC composite signals, the sampling frequency is usually set to 4 times the frequency of the color sub-carrier, that is, 4 fsc. This is because digital color demodulation processing in the following stage becomes simplified if this sampling frequency is adopted. If the sampling frequency is thus set to 4 fsc, the number of samples in the horizontal direction (lateral direction) becomes 910, as shown in FIG. 5. Considering an aspect ratio of 3:4 with 525 lines in the vertical direction, in the case of 700 (=525.times.4/3) samples, the pixel (picture element) becomes square as shown by broken lines in FIG. 6. In the case of 910 samples, however, the shape of the pixel (the hatched portion in FIG. 6) becomes about 30% longer in the vertical direction than in the horizontal. When the same processing as for output signals from a scanner for reading an original is performed using such a vertically-long pixel, printing having a correct aspect ratio cannot be obtained in some cases. That is, there is the problem that when, for example, a printer performs image formation assuming that the digital image data it receives have been sampled with an aspect ratio of 1:1, a correct aspect ratio is not provided in the resulting printing.
In order to solve such problem, the aspect ratio may be changed in accordance with the printer. This approach, however, necessitates a complicated operation. In addition, if it is desired to deal with a plurality of kinds of video signals, complicated setting of operation conditions is further needed.
In order to solve the above-described problems, the assignee of the present application has proposed a technique in U.S. application Ser. No. 592,991 filed Oct. 4, 1990. This technique, however, still has room for improvement from the viewpoint of operability.